In the process of manufacturing cigarettes, it is necessary to test each cigarette and, if a flaw is detected, the flawed cigarette must be rejected. In this testing process, it has become standard to connect a test air line to the end of each cigarette for a very short interval of time during which air under pressure is injected into the cigarette and certain measurements are made. A sealing arrangement for this purpose is described in copending U.S. patent application Ser. No. 469,895, Krappitz et al., filed Feb. 25, 1983. That apparatus permits forming a seal at the end of a cylindrical body, particularly a cigarette, in such a way that a test air line is coupled in a precisely coaxial, concentric arrangement with the cigarette with a perfect seal.
The arrangement described therein avoids the disadvantages of previously known pneumatic test methods and apparatus as they are described and shown, for example, in German OS 2,150,186, OS 2,324,055 and OS 2,753,835.
As discussed in connection with the background of the previously mentioned copending application, the previously used devices involved essentially cylindrical or slightly conical sealing bodies with an axial bore and a connecting or seaing surface which is concave somewhat in the manner of a cup or ball, or the interior of a trumpet mouthpiece, the larger diameter thereof being somewhat larger than the end of the article being tested. The sealing surface of such an arrangement is moved up to the end of a cigarette and is pressed against the end so that the end of the cigarette is slightly radially compressed. Unfortunately, in such devices it is entirely possible for their to be off-center contact between the sealing body and the cigarette. Misalignments or imprecisions in this connection may not be balanced out so that more or less serious impairments of the sealing can occur.
The arrangement discussed in Ser. No. 469,895, disclosed a sealing arrangement which overcame these disadvantages, permitting the outer surface of the cylindrical end of the cigarette to be enclosed in a perfect sealing arrangement in which the end of the cigarette is not impaired in any way. Furthermore, the principle applied in that arrangement automatically guarantees centering and perfectly reliable and even sealing.
The apparatus disclosed therein operates in such a way that an inner flange of a sealing body is stretched open and enlarged and then is allowed to relax and close around the end of the cigarette. The sealing arrangement can be moved in its open position to the end of the cigarette or the like which is to be sealed and then is allowed to close so that the end of the cigarette is encompassed until the seal is broken by again stretching open the sealing body and moving it away from the end of the cigarette.
In order to carry out the opening and closing movement, a holding body engaging the outside flange of the sealing body is moved axially back and forth with respect to the sealing body support. The means for the mechanical drive and control of the opening and closing movement of the seal proposed in Ser. No. 469,895 comprises a guide arrangement with a cam path along which spring forks travel, the legs of the forks engaging recesses in the holding bodies. While this apparatus is capable of functioning in a very suitable fashion, because of the fact that it is an entirely mechanical device and involves a degree of friction between relatively moving parts, it is unavoidable that a certain amount of wear and, therefore, degeneration of the mechanical operation of these components occurs.